Heretofore, lint screens and the like have been provided generally in ranges having ovens equipped with penthouses wherein the screen is positioned between the main body of the oven and the penthouses across the air passageway on both sides of the fans for manual cleaning and removal. Such devices are illustrated in U.S. Pat. No. 2,083,141. It has been found in practice, that the screens become clogged because of the fact that operators neglect to properly service such manual filter devices.
Efforts to provide automatically operable lint screens which move continuously, or which move responsive to variation in pressure which would be indicative of excessive clogging have been unsuccessful. Such attempts have generally been made utilizing endless screen or belt constructions wherein a brush is of necessity provided only on the outside of the belt to remove the lint. In such devices, two passes or widths of screen move in connection with each winding device so that there is always a space between the passes. This space becomes clogged with lint which is entrapped therein because there is no place for the lint which works in between the passes of the screen to escape.
Accordingly, it is an important object of this invention to provide an improved apparatus for removing lint which becomes airborne due to impingement of heated air against the fabric being treated in the range. The lint laden air must be filtered so as to remove the airborne particles at a point in the air stram after the air is applied to the fabric and before it is returned to the heater. All webs producing lint and the like are beneficially treated through the practice of the invention, including cotton and acrylic fabrics, although usefulness with fabric constructed of monofilament nylon, for example, may be limited.
In ovens of the type wherein the invention is contemplated to be used, almost entirely recirculated air is utilized, although from about 3 to 5% air is exhausted and replaced with uncirculated air. It is important that the lint particles be intercepted by the filter or screen material so that they will not get into the duct and thus be returned to the cloth. More importantly, the duct work is to be protected and in particular, the apertures, holes, or other nozzle devices of the duct work are to be protected from clogging due to contamination with lint.
Another important object of the invention is the avoidance of fires because lint is prevented from accumulating in large collection areas, as in the dead air spaces occurring in the penthouses, which accumulations may then fall within the flames inducing a fire in the apparatus.
It is contemplated that the lint screen assembly structure of the present invention be utilized one on each side of the fans in the air passageway between the cloth and the heated area within the penthouses. It may be possible to use more than one lint screen in each position, but such must be spaced sufficiently to permit cleaning out of the areas between the single passes as well as in the structure for rolling a length of screen up on the sides of the oven.
The invention also contemplates rolling a length of lint filter screen to one side of the oven and then after such filter screen winding is complete, together with the attendant cleaning, the entire screen is again fed to the other, or feed side in a single movement from whence it is then incrementally fed preparatory through another complete rewinding cycle.
Apparatus constructed in accordance with the present invention is also useful with low profile ovens wherein the lint laden air comes off of the cloth and then down into the screen due to the negative pressure of the fan. In instances such as the low profile ovens wherein the burner or coils or electrical heaters or open flame heaters are positioned at the bottom of the body of the oven, the pass of the width of lint screen material must usually be vertical in order to cover the air passageway to the burner or other heat source.